1. Field of the Invention
The present invention relates to a heat sink for cooling a power semiconductor module of a unitary structure in which power elements such as IGBTs (Insulated Gate Bipolar Transistors) constituting major parts of an electric power control device such as a general-purpose inverter or the like are incorporated.
2. Description of Related Art
Heretofore, in the general-purpose inverter for performing, for example, variable control of rotation speed (rpm) of an electric motor designed for industrial appliance, a power semiconductor module which incorporates therein IGBTs or the like is employed as a major device constituting a major part of the inverter circuit. The power semiconductor module generates heat in the course of operation. Consequently, cooling of the power semiconductor module is necessarily required. To this end, a heat sink is mounted on the power semiconductor module.
As a typical example of the heat sink, there may be mentioned the one in which a cover member is fit on a base member on which the power semiconductor module is mounted to form a hollow passage through which cooling air can flow. Disposed within the hollow passage is a corrugated fin which is formed by bending a thin plate in a corrugated shape. For more particulars, reference may have to be made to, for example, Japanese Patent Application Laid-Open Publication No. 257296/2001 (JP-A-2001-257296).
With the structure of the heat sink mentioned above, the heat emitting area which is brought into contact with the cooling air flow can certainly be increased owing to the wave-like structure of the corrugated fin with the heat transfer being thereby promoted. However, since the corrugated fin is fixedly secured to the base member and the cover member by brazing, the efficiency involved in assembling the heat sink is poor, as a result of which the manufacturing cost increases, giving rise to a problem.